OpenBSD has issued an update for xdm. This fixes a security issue, which potentially may allow malicious users to gain unintended access to a system. A CVS version of XFree86 xdm, which is included in some versions of OpenBSD, has an error that causes it to listen for queries on a random TCP socket, even though requestPort is set to 0 in the configuration file.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/33455/sa11723.txt
Source: https://packetstormsecurity.com/files/33455/Secunia-Security-Advisory-11723.html